Headlight.



A. H. PFUND.

HEADL'IGHI.

APPLICATION FILED JULY I, 19| 7.

Patented Apr. 1, 1919.

@theme14 'AUGUST Hannan rrnnn, or narfrrnconn, mantenne.

Hnnnrirsnr.

To all whom t may concern: f l

Be it known that I, AUGUST HERMAN Primo, a citizen of theIlnited States' of America, residing-at the city'of Baltimore, 1 State of Maryland,yhav e invented -certain new and useful'Improvementsv in Head- .The increased. danger incident to autorno- -bile traiic at night 'owing to the glare of the headlights is well-kriwn..1l In city iving the powerfull lightsv areextinguis ed or fdimmed and the main difficulty insluch drivthe light.- This' penumbra is insufficientlyv l height.

ing is that su'icient'illuminatio 4roads where 'powerful llights are thought provide that 'lights used in the city or country shall not The use of screens or dimmers covering all but a smallportion ofthe reflector is well? known but such coveringsstop the majority of the rays so that the eflciencv is very low and the illuminated ieldi'divided from the wholly shaded field by apenumbr'a the width of which increases withv the distance from lighted and'at no great-.distance covers a Vvery considerable. portion of the field of illumination.

mlnation an inverted lmage of anfopaque screen, thus limiting the field of illumination and protectingthe eyes. .This image is welldelined asto the edgetof the screen and the field of intense illumination extends up to' the line forming the edge of the screen, givilluminated area.- This line may be made f straight and horizontal and `niay be projected at lthe, required elevation with the dark area above. In this way the beneficial illuminative eect on the road is retained in full and the glare avoided in complete com.

l Specication of Letters Patent.

f cannot be had within the law. vOnthe out-of-town glare at a given distance and lng or interfering with the'vision o'f pedes' trlans or drivers-of passlng' vehicles. 'This is done by projecting-across the field of 'illu-l Patenten?. Apr. il.,

application me@ July?, 1917. serial no. traine.

means of the usual source of il umination' and refiector with a lens in place of the ordi- 1 i 1 nary glass window, a portion of the reflector lights of which the following 1s a specifica-v,

lent, and the screen covers the reflector forward of the principal focus on the side of the optic plane remote from or below the vvsource of lllumination, the screen terminala` ingi'n a straight line parallel to the elements of the cylinder at or near the princi a1 focus o'r focal line of the lens or lenses an prefer'- y ably coincident with such focal line. By 4.op tic plane, I mean a plane containing the principal focus ofthe lens or vlenses andvi'n' a yplano-cylindrical lens at -right angles to the vplane surface ofthe lens;

' In order to accomplish the eec't specified in the law referred to which forbids glare ata certain distance and height, I preferto use the cylindrical lens with its axls hori.

" z ontal, the focus being below thesource cof i l1 ht and the screen having its uppered w ich in the optic plane horizontal and A preferably coinciding with the principal "focus of the lens. i i

.An important feature of the invention is that the lens and screen combined may be l Y furnished as' stock accessories adapted to be The obj ect of the present invention iste' so control the distribution of the light rays as'. to give suiiicient illumination without blindused in 'any light by merely removin'gthe old p glass and inserting in place of it, the lens glass and screen which comes fastened tothe glass. The entire outfit assembled new is ofV lfoourse equally within the scope of myinvention.`

'have illustrated a headlight 1 which. so far v as the reflector 2 with a lamp or source of illumination 3 is concerned, maybe the ordinary commercial article. To this I have In "the accompanying drawing, I have .illustrated an automobile headlight constructed in accordance with the form of myg I"invention, which is now considered the preroc screen relatively to the lens.

added a glass fl -vvhichis substituted for the usual iront glass or Winder.7 in such lights, and a screen shown in the iorin ot a scoop with the `rontedge closed by a transverse Wall.' rthis glass includes a lens 6 'which to the most perfect results should be "I idrical or approachingl cylindrical, and red undue thickness1 this lens may bes slioivn is, made `lwith tivo or more ical or lens surtaces or steps t', 89 their principal foci 9 in the same plane, ed to herein as the optie plane l0, but principal loci are not necessarily `coin- "'"ie lens or lenses as shown are plano-convert7 having1 the convex side ind or to the rear. rEhe screen effect may be had by any suitable covering; as painting, c; "il/there the device is merely used as means lor relitting an old lama)7 the scoop or screen 5 may be convenienti. Eastcned to the bottom of the glass or lens el to be in :4 ou with the glass. ln this Way, it is possible tor the manuiacturer to determine once for all the position oi' the top edge ot the ln the torni of the invention shown, the lens or lenses ipy a compara-tively small area at the center ot' the glass though as great an area desired may be occupied by ,the lens or 'l lin the form shown, the surrounding portion ll is ground or ronghened to screen made plain to permit the direct ot the light to be projected downward iront et the machine though is orno great importance.

The screen 5 which broadly is merely a diffusing or absorbent surface, may be 'provided and secured in anyy suitable manner, and painted White at the lovver or outer portion l5 and blaclr at thev upper portion lll,

.or otherwise so long as its surface is nonglare producing. ,ds illustrated, to give a sharp line olf-demarcation between the light hield and the screen image or dai-lr field, the wall of the screen at l5 is made sub siantially and 'vertical with a straight top edpge, the edge to be projeeted being indi *ed by reterence character lo. rllhis ic in the optical plane l0 oit the lenses and rably coincident with the locus oi the y louer or near lens or step 8.

'will be understood that `while in the arranpgeinent7 l place the screen 6 horizontal, making the optie plane of the lons or and the principal focus yhori- .ntal so that the projected edge of the lungi meen is likewise horizontah 'the screen and le s may be tipped to any desired angle.,

lt 1s ot" course understood that the rays cross in front of the lens so that the illuminated d is below the projected edge itl and the 'f `field above.

the operation olf my invention, the edge plane which selthe light and the area l2 opposite vcally and in detail in the bottom oit the reflector with its edge i i l ai in the optic plai at the focus oit the lens, is projectedfo to iniinityi) being reproduced on any s i "which it encounters with practically' distinctness at almost any distance9 the il itection ot the Aoutline being of course pendent on the perfection of the lens, iield above the optic lPlane el the lens or lenses is dark, the rays from the entire snritace et the redector in line with the lens be ing1 projected forward at or beneath the optic divides the darli area and the area which is most highly illumina-ted, and the most efficient illumination which can i torni to the non-glare requirement 1 results.v Y

lWhile the lens sections? and d ierred to as having their principal the same plane, this9 though preter# not essential to the construction illusi The important consideration is that'tlt jected edge i6 shall be in the Jlocal plain et the lens surfacel 8, preferably at the principal locus. The importent consideration 're-- gardly the lens surface 7 is that it shall all the rays that it receives dormiva. prevent glare and fot) leave thev projected er lo sharp and Well-defined. ln any ment ot' the device Within the limits ni t netined, what may be termed an image ol the screen is projected forwardly at the top el the bar oi light, and the eilect is so 'mai :ed that vve have a sharp transition trom li to dark so Well dened that the top or a mans tace 50 feet away may be hidden in i..

darkness While the lower portion is illpnai nated. This engeet is entirely dependent the arrangement of the condensing device in combination With the screen edge and image-forming lens.

l have thus described my invention speciliorder that its nature bev fully understood; c terms herein are used and' operation ma however, the speer descriptively 'rather than in their limiting;

sense and the scope of the invention is denned in the claims.

ll claim: y

jl. ln a headlight in combination a condenser, a source oit illumination, a le? ing an optic plane, and means tor che ing a portion of the rays, said means terminating in an edge in the optic plane oit said lens whereby an image of said obstruct# ing means With' a Well-dened edge separ ing an intensely illuminated neld l i e dark field Without intervening pennr. projected forward in place oi the field of illumination. y

2. ln a headlight in combination t of illumination, a reilector, a cvlinrh a non-rellecting` surface below the light, i minating at its upper edge, substantially in the optical plane of said lens? the reflector? source of illumination and the lens being ar l t SCT) ranged to project a well-defined image of said edge, servingto divide an intensely illuminated field and an adjacent dark field the illuminated field being below the image.

3. In a headlight in combination, a source of light, a condenser, a cylindrical imageforming lens, an edge substantially parallel to the elements of the lens near the principal focus, a non-reflecting surface extending downward from said edge and shading the reflector below the optic plane of the lens whereby a well-defined image of the straight edge is projected forward,`the same separating an intensely illuminated 'field below from a dark field above.

4. In a headlight in combination a parabolic reflector, a source of light at or near the principal focus of the parabola, a cylindrical image-forming lens, an edge in the optic plane and substantially-parallel to and near the principal focus of the lens, 'a nonreflecting surface extending from the straight edge so there is no reflection from below the focal plane, whereby an image of the4 said edge is projected into infinity, the same separating the most intensely illuminated portion of the lighted field from a darkv area above. V

5. In a headlight in combination, a condenser, a source of illumination, an imageforming lens having its principal focus` definedby a*V line transverse to the axis of the headlight, and a non-reflecting surface terminating at its upper extremity in an edge parallel to. and in the horizontal plane with said princlpal focus.

6. Ina headlight in combination a para-U bolic reflector, a source of illumination at the optical center of the parabola, a planocylindrical lens having its principal focus defined by a line transverse to the axis ofthe headlight and a screen or non-reflecting surface terminating in an edge near the focal plane of the lens, the screen covering the reflector forward of the said line and. below the optic plane of the lens.

7. In combination a source of light, a condensing refiector,.a plano-cylindrical imageforming lens and a non-reflecting surface terminating in a top edge in the optic plane of the lens.

8. In cnbination a source of light, a condensing reflector, a plano-cylindrical imageforming lens and a non-reflecting surface i terminating in a top edge substantially coincident with the principal focus of sald lens and in the optie plane of the lens.

Signed by me at Baltimore, Maryland,

this 6th day of July, 1917. AUGUST. HERMAN PFUND.

Witnesses: PORTER H. FLAU'rr, 4Znnna KUHN. f 

